👙 Bra Size Calculator
Find your band size and cup size from your band and bust measurements.
Your Measurements
Your Result
| Bust − Band | Cup Size |
|---|---|
| 0" | AA |
| 1" | A |
| 2" | B |
| 3" | C |
| 4" | D |
| 5" | DD / E |
| 6" | DDD / F |
| 7" | G |
| 8" | H |
This uses a common traditional sizing method. Sizing systems vary by brand and country, so use this as a starting point and try before you buy when possible.
How the Bra Size Calculator Works
Bra sizing combines a band measurement (taken snugly around your ribcage, just under the bust) with a bust measurement (taken around the fullest part of your bust). The difference between the two determines your cup size.
Formula
Cup difference = Bust measurement − Band measurement
Cup size: 0"=AA, 1"=A, 2"=B, 3"=C, 4"=D, 5"=DD/E, 6"=DDD/F, and so on, one letter per inch
Tips for Measuring
- Measure the band snugly, but not tight, directly under your bust.
- Measure the bust around the fullest part while wearing a non-padded bra.
- Sizing varies between brands — treat this as a helpful starting estimate.
Frequently Asked Questions
Why does band size add 4 or 5 inches?
This traditional method adjusts your snug ribcage measurement to account for how bra bands are constructed and sized, rounding to the nearest standard band number.
Why do bra sizes vary between brands?
There's no single global sizing standard, so cup and band proportions differ by brand and country. Always check a brand's specific size chart when possible.
What if my cup difference is more than 8 inches?
Larger differences continue the same one-letter-per-inch pattern (I, J, K, and so on), though not all brands carry every size.